Bonding system

ABSTRACT

A bonding system includes a substrate transfer device configured to transfer a first substrate and a second substrate to a bonding apparatus, a first holding plate configured to hold the first substrate from an upper surface side, and a second holding plate disposed below the first holding plate and configured to hold the second substrate from a lower surface side so that the second substrate faces the first substrate. The substrate transfer device includes a first holding part capable of holding the first substrate from the upper surface side, and a second holding part disposed below the first holding part and capable of holding the second substrate from the lower surface side. The first holding part and the second holding part are configured to receive and hold the first substrate and the second substrate at the same time from the first holding plate and the second holding plate.

CROSS-REFERENCE TO RELATED APPLICATION

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2016-137635, filed on Jul. 12, 2016, the entire contents of which are incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a bonding system.

BACKGROUND

In order to meet the demand for higher integration of semiconductor devices, use of a three-dimensional integration technique to stack semiconductor devices in three dimensions has been proposed. Systems adopting this three-dimensional integration technique utilize a bonding system for bonding substrates such as, e.g., semiconductor wafers (hereinafter referred to as “wafers”) or the like.

Such a bonding system includes a surface modifying apparatus for modifying the surfaces of first and second substrates to be bonded, a hydrophilizing apparatus for hydrophilizing the modified first and second substrates, and a bonding apparatus for bonding the hydrophilized first and second substrates by a van der Waals force and hydrogen bonding (an intermolecular force). The bonding system further includes a substrate transfer device for transferring the first and second substrates between the respective apparatuses.

However, in the substrate transfer device described above, for example, it is configured to receive the processed first and second substrates one at a time from an apparatus for performing a process before bonding and to transfer the first and second substrates to the bonding apparatus. Therefore, in the above-described bonding system, the process of transferring a set of first and second substrates to the bonding apparatus is lengthy.

SUMMARY

Some embodiments of the present disclosure provide a bonding system capable of shortening a processing time for transferring first and second substrates to a bonding apparatus.

According to one embodiment of the present disclosure, there is provided a bonding system which includes a substrate transfer device configured to transfer a first substrate and a second substrate to a bonding apparatus for bonding the first substrate and the second substrate, a first holding plate configured to hold the first substrate from an upper surface side, and a second holding plate disposed below the first holding plate and configured to hold the second substrate from a lower surface side so that the second substrate faces the first substrate. The substrate transfer device includes a first holding part capable of holding the first substrate from the upper surface side, and a second holding part disposed below the first holding part and capable of holding the second substrate from the lower surface side so that the second substrate faces the first substrate. Further, the first holding part and the second holding part are configured to receive the first substrate held by the first holding plate and the second substrate held by the second holding plate at the same time from the first holding plate and the second holding plate, and to hold the first substrate and the second substrate.

BRIEF DESCRIPTION OF DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the present disclosure, and together with the general description given above and the detailed description of the embodiments given below, serve to explain the principles of the present disclosure.

FIG. 1 is a schematic plan view showing a configuration of a bonding system according to an embodiment.

FIG. 2 is a schematic side view showing the configuration of the bonding system according to the embodiment.

FIG. 3 is a schematic side view of a first substrate and a second substrate.

FIG. 4 is a schematic side view showing a configuration of a position adjusting device.

FIG. 5A is a schematic plan view showing a configuration of an inverting transition.

FIG. 5B is a schematic side view showing the configuration of the inverting transition.

FIG. 6A is a schematic plan view showing a configuration of a transfer device.

FIG. 6B is a schematic side view showing the configuration of the transfer device.

FIG. 7 is a schematic side view showing a configuration of a substrate temperature control device.

FIG. 8A is a view for explaining the operations of the transfer device and the substrate temperature control device.

FIG. 8B is a view for explaining the operations of the transfer device and the substrate temperature control device.

FIG. 8C is a view for explaining the operations of the transfer device and the substrate temperature control device.

FIG. 8D is a view for explaining the operations of the transfer device and the substrate temperature control device.

FIG. 8E is a view for explaining the operations of the transfer device and the substrate temperature control device.

FIG. 8F is a view for explaining the operations of the transfer device and the substrate temperature control device.

FIG. 9 is a view for explaining the detection of positions of an upper wafer and a lower wafer by a position detecting part.

FIG. 10 is a schematic plan view showing a configuration of the bonding apparatus.

FIG. 11 is a schematic side view showing the configuration of the bonding apparatus.

FIG. 12 is a schematic side view showing an internal configuration of the bonding apparatus.

FIG. 13 is a schematic side view showing a configuration of an upper chuck and a lower chuck.

FIG. 14 is a schematic plan view of the upper chuck as viewed from below.

FIG. 15 is a schematic plan view of the lower chuck as viewed from above.

FIG. 16A is an operation explanation view of the bonding apparatus.

FIG. 16B is an operation explanation view of the bonding apparatus.

FIG. 16C is an operation explanation view of the bonding apparatus.

FIG. 16D is an operation explanation view of the bonding apparatus.

FIG. 16E is an operation explanation view of the bonding apparatus.

FIG. 16F is an operation explanation view of the bonding apparatus.

FIG. 16G is an operation explanation view of the bonding apparatus.

FIG. 16H is an operation explanation view of the bonding apparatus.

FIG. 17 is a flowchart showing a part of a processing procedure of a process executed by the bonding system.

DETAILED DESCRIPTION

Hereinafter, embodiments of a bonding system disclosed herein will be described in detail with reference to the accompanying drawings. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present disclosure. However, it will be apparent to one of ordinary skill in the art that the present disclosure may be practiced without these specific details. In other instances, well-known methods, procedures, systems, and components have not been described in detail so as not to unnecessarily obscure aspects of the various embodiments.

<1. Configuration of Bonding System>

First, a configuration of a bonding system according to an embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic plan view showing a configuration of a bonding system according to an embodiment, and FIG. 2 is a schematic side view thereof. Further, FIG. 3 is a schematic side view of a first substrate and a second substrate. In the following description, in order to clarify the positional relationship, an X axis direction, a Y axis direction and a Z axis direction orthogonal to each other are defined. The Z axis positive direction is defined as a vertical upward direction. In each of the drawings including FIGS. 1 to 3, only the components necessary for explanation are shown, and the illustration of general components may be omitted in some cases.

The bonding system 1 according to this embodiment shown in FIG. 1 is configured to form a laminated substrate T by bonding a first substrate W1 and a second substrate W2 (see FIG. 3).

The first substrate W1 is, for example, a substrate in which a plurality of electronic circuits is formed on a semiconductor substrate such as a silicon wafer or a compound semiconductor wafer. The second substrate W2 is, for example, a bare wafer in which no electronic circuit is formed. The first substrate W1 and the second substrate W2 have approximately the same diameter.

An electronic circuit may be formed on the second substrate W2. As the aforementioned compound semiconductor wafer, it may be possible to use, for example, a wafer which contains gallium arsenide, silicon carbide, gallium nitride, indium phosphide or the like. However, the present disclosure is not limited thereto.

In the following description, the first substrate W1 may be referred to as “upper wafer W1”, the second substrate W2 may be referred to as “lower wafer W2”, and the laminated substrate T may be referred to as “laminated wafer T.”

In the following description, as shown in FIG. 3, the substrate surface of the upper wafer W1 to be bonded to the lower wafer W2 will be referred to as “bonding surface W1 j” and the substrate surface on the side opposite to the bonding surface W1 j will be referred to as “non-bonding surface W1 n.” Likewise, the substrate surface of the lower wafer W2 to be bonded to the upper wafer W1 will be referred to as “bonding surface W2 j” and the substrate surface on the side opposite to the bonding surface W2 j will be referred to as “non-bonding surface W2 n.”

As shown in FIG. 1, the bonding system 1 includes a loading/unloading station 2 and a processing station 3. The loading/unloading station 2 and the processing station 3 are arranged side by side in the order of the loading/unloading station 2 and the processing station 3 along the X axis positive direction. The loading/unloading station 2 and the processing station 3 are integrally connected to each other.

The loading/unloading station 2 includes a mounting table 10 and a transfer region 20. The mounting table 10 includes a plurality of mounting plates 11. On the respective mounting plates 11, cassettes C1, C2 and C3 for accommodating a plurality of substrates (for example, 25 substrates) in a horizontal state are mounted, respectively. The cassette C is a cassette for accommodating the upper wafer W1, the cassette C2 is a cassette for accommodating the lower wafer W2, and the cassette C3 is a cassette for accommodating the laminated wafer T. In the cassettes C1 and C2, the upper wafer W1 and the lower wafer W2 are accommodated with their orientations aligned such that the bonding surfaces W1 j and W2 j face upward.

The transfer region 20 is disposed adjacent to the mounting table 10 on the side of the X axis positive direction. In the transfer region 20, a transfer path 21 extending in the Y axis direction and a transfer device 22 movable along the transfer path 21 are provided. The transfer device 22 is also movable in the X axis direction and is rotatable around the Z axis. The transfer device 22 transfers the upper wafer W1, the lower wafer W2 and the laminated wafer T between the cassettes C1 to C3 mounted on the mounting plates and the third processing block G3 of the processing station 3 to be described later.

The number of cassettes C1 to C3 mounted on the mounting plates 11 is not limited to that shown in the drawings. In addition to the cassettes C1, C2 and C3, a cassette for recovering a defective substrate or the like may be mounted on the mounting plates 11.

In the processing station 3, a plurality of, for example, three, processing blocks G1, G2 and G3 having various apparatuses are provided. For example, a first processing block G1 is provided on the rear side of the processing station 3 (on the side of the Y axis positive direction in FIG. 1), and a second processing block G2 is provided on the front side of the processing station 3 (the side of the Y axis negative direction in FIG. 1). A third processing block G3 is provided on the loading/unloading station 2 side (on the side of the X axis negative direction in FIG. 1) of the processing station 3.

In a region surrounded by the first processing block G1 to the third processing block G3, a transfer region 60 is formed. In the transfer region 60, a transfer device 61 is disposed. The transfer device 61 includes a transfer arm which is movable in the vertical direction and the horizontal direction and rotatable around the vertical axis. The transfer device 61 is configured to be able to receive the upper wafer W1 and the lower wafer W2 held by a below-described substrate temperature control device 42 at the same time. A detailed configuration of the transfer device 61 will be described later with reference to FIGS. 6A and 6B.

The transfer device 61 moves within the transfer region 60 and transfers the upper wafer W1, the lower wafer W2 and the laminated wafer T to predetermined apparatuses disposed in the first processing block G1, the second processing block G2 and the third processing block G3 adjacent to the transfer region 60.

In this regard, the transfer of the upper wafer W1, the lower wafer W2 and the laminated wafer T by the transfer device 61 is performed in a normal pressure atmosphere. The normal pressure is, for example, an atmospheric pressure. However, the normal pressure does not need to be exactly the same as the atmospheric pressure and may include a pressure range of, for example, ±10 kPa with respect to the atmospheric pressure. In addition, the transfer device 61 is an example of a substrate transfer device.

In the first processing block G1, a load lock chamber 31, a transfer chamber 32, a surface modifying apparatus 33 and a surface hydrophilizing apparatus 34 (see FIG. 2) are disposed.

The load lock chamber 31 is located at a position most distant from the loading/unloading station 2 in the first processing block G1 and is disposed adjacent to the Y axis positive direction side of the transfer region 60 via a gate valve 36 a. The transfer chamber 32 is disposed adjacent to the X axis negative direction side of the load lock chamber 31 via a gate valve 36 b, and the surface modifying apparatus 33 is located at a position closest to the loading/unloading station 2 in the first processing block G1 and is disposed adjacent to the X axis negative direction side of the transfer chamber 32 via a gate valve 36 c.

In the load lock chamber 31, the upper wafer W1 and the lower wafer W2 are delivered between the transfer device 61 and the surface modifying apparatus 33. Specifically, a plurality of transitions 31 a 1 and 31 a 2 is provided inside the load lock chamber 31 (see FIG. 2). The transitions 31 a 1 and 31 a 2 are configured to mount the upper wafer W1 or the lower wafer W2. In this embodiment, for example, the transition 31 a 1 mounts the upper wafer W1 or the lower wafer W2 loaded from the transfer device 61 into the surface modifying apparatus 33, and the transition 31 a 2 mounts the upper wafer W1 or the lower wafer W2 unloaded from the surface modifying apparatus 33 to the transfer device 61.

As shown in FIG. 2, the transitions 31 a 1 and 31 a 2 are stacked and disposed in the vertical direction. However, the present disclosure is not limited thereto. For example, the transitions 31 a 1 and 31 a 2 may be disposed so as to be adjacent to each other in a plan view. The transitions 31 a 1 and 31 a 2 are an example of a substrate mounting table.

A vacuum pump 31 c (see FIG. 2) is connected to the load lock chamber 31 via a suction pipe 31 b. Thus, for example, when the gate valves 36 a and 36 b are closed and when the vacuum pump 31 c is operated, the interior of the load lock chamber 31 is depressurized into a depressurized atmosphere. On the other hand, for example, when the gate valve 36 a is opened, the interior of the load lock chamber 31 communicates with the transfer region 60 whose interior is kept under an atmospheric pressure atmosphere. Thus, the atmosphere in the load lock chamber 31 becomes an atmospheric pressure atmosphere. As described above, the load lock chamber 31 is configured so that the atmosphere in the load lock chamber 31 can be switched between the atmospheric pressure atmosphere and the depressurized atmosphere.

In the transfer chamber 32, a transfer device for surface modifying apparatus (hereinafter referred to as “modifying transfer device”) 32 a is disposed. The modifying transfer device 32 a includes, for example, a transfer arm which is movable in the vertical direction and the horizontal direction and rotatable around the vertical axis. The modifying transfer device 32 a receives, for example, the unmodified upper wafer W1 or the like mounted on the transition 31 a 1 of the load lock chamber 31 and transfers the unmodified upper wafer W1 to the surface modifying apparatus 33. Furthermore, the modifying transfer device 32 a transfers the upper wafer W1 or the like modified in the surface modifying apparatus 33 to the load lock chamber 31 and mounts/places the upper wafer W1 or the like on the transition 31 a 2 (see FIG. 2).

A vacuum pump 32 c (see FIG. 2) is connected to the transfer chamber 32 via a suction pipe 32 b. When the vacuum pump 32 c is operated, the interior of the transfer chamber 32 is depressurized into a depressurized atmosphere. The gate valve 36 b is opened when the load lock chamber 31 is in the depressurized atmosphere. Similarly, the gate valve 36 c is opened when the surface modifying apparatus 33 is in the depressurized atmosphere.

Therefore, the transfer chamber 32 is constantly kept under the depressurized atmosphere by the vacuum pump 32 c. In this way, the modifying transfer device 32 a of the transfer chamber 32 is disposed adjacent to the load lock chamber 31 and is configured to transfer the upper wafer W1 and the lower wafer W2 between the load lock chamber 31 and the surface modifying apparatus 33 under the depressurized atmosphere.

The surface modifying apparatus 33 is configured to modify the bonding surfaces W1 j and W2 j of the upper wafer W1 and the lower wafer W2. A vacuum pump 33 c (see FIG. 2) is connected to the surface modifying apparatus 33 via a suction pipe 33 b. When the vacuum pump 33 c is operated, the interior of the surface modifying apparatus 33 is depressurized into a depressurized atmosphere. As with the transfer chamber 32, the surface modifying apparatus 33 is also constantly kept in the depressurized atmosphere.

Therefore, the surface modifying apparatus 33 modifies the bonding surfaces W1 j and W2 j of the upper wafer W1 and the lower wafer W2 under the depressurized atmosphere. More specifically, the surface modifying apparatus 33 breaks the bonds of SiO₂ on the bonding surfaces W1 j and W2 j of the upper wafer W1 and the lower wafer W2 to form single-bond SiO₂, thereby modifying the bonding surfaces W1 j and W2 j so that the bonding surfaces W1 j and W2 j can be subsequently hydrophilized with ease.

In the surface modifying apparatus 33, an oxygen gas, which is a process gas, is excited into plasma under a processing apparatus and is ionized. Then, the bonding surfaces W1 j and W2 j of the upper wafer W1 and the lower wafer W2 are irradiated with the oxygen ions, whereby the bonding surfaces W1 j and W2 j are subjected to plasma treatment and are modified.

The internal volume of the load lock chamber 31 described above is set to become smaller than the internal volume of the surface modifying apparatus 33 or the transfer chamber 32. However, the present disclosure is not limited thereto.

Now, the transfer of the upper wafer W1 in the load lock chamber 31, the transfer chamber 32 and the surface modifying apparatus 33 configured as above will be described in detail. Since the lower wafer W2 is transferred in the same manner as the upper wafer W1, the following description is also generally applicable to the transfer of the lower wafer W2. It is assumed that the gate valves 36 a. 36 b and 36 c are all closed.

Specifically, first, when the unmodified upper wafer W1 is transferred to the front of the load lock chamber 31 by the transfer device 61, the gate valve 36 a is opened and the unmodified upper wafer W1 is mounted on the transition 31 a 1 of the load lock chamber 31. In addition, when the unmodified upper wafer W1 is mounted on the transition 31 a 1, there may be a case where the upper wafer W1 or the lower wafer W2 already modified in the previous process is mounted on the transition 31 a 2. In such a case, after mounting the unmodified upper wafer W1 on the transition 31 a 1, the transfer device 61 may receive the upper wafer W1 or the lower wafer W2 mounted on the transition 31 a 2 and may remove the upper wafer W1 or the lower wafer W2 from the load lock chamber 31.

Next, the gate valve 36 a is closed, the vacuum pump 31 c is operated, and the load lock chamber 31 is depressurized into a depressurized atmosphere.

Next, the gate valves 36 b and 36 c are opened, and the modifying transfer device 32 a transfers the upper wafer W1 mounted on the transition 31 a 1 to the surface modifying apparatus 33. Subsequently, the gate valves 36 b and 36 c are closed, and the modifying process of the upper wafer W1 is performed by the surface modifying apparatus 33.

When the modifying process is completed, the gate valves 36 b and 36 c are opened. The modifying transfer device 32 a takes out the upper wafer W1 from the surface modifying apparatus 33 and transfers the upper wafer W1 to the transition 31 a 2 of the load lock chamber 31. Next, after the gate valves 36 b and 36 c are closed, the gate valve 36 a is opened so that the internal atmosphere of the load lock chamber 31 is switched from the depressurized atmosphere to the atmospheric pressure atmosphere.

Then, the transfer device 61 takes out the modified upper wafer W1 from the transition 31 a 2 of the load lock chamber 31 and transfers the modified upper wafer W1 to the surface hydrophilizing apparatus 34 where the next process is performed.

As described above, the bonding system 1 according to the present embodiment includes the load lock chamber 31 in which the upper wafer W1 and the lower wafer W2 are delivered between the transfer device 61 and the surface modifying apparatus 33 and in which the atmosphere can be switched between the atmospheric pressure atmosphere and the depressurized atmosphere.

Thus, in the bonding system 1, it is possible to shorten the processing time of the upper wafer W1 and the lower wafer W2. That is to say, when the upper wafer W1 and the lower wafer W2 are loaded and unloaded to and from the surface modifying apparatus 33, if the internal pressure of the load lock chamber 31 is made switchable, it is possible for the surface modifying apparatus 33 to carry out the modifying process while maintaining the depressurized atmosphere. Accordingly, in the surface modifying apparatus 33, the process of switching the atmospheric pressure atmosphere to the depressurized atmosphere is not required. This makes it possible to shorten the time required for the modifying process of the upper wafer W1 and the lower wafer W2.

The internal volume of the load lock chamber 31 is set to become smaller than the internal volume of the surface modifying apparatus 33 or the transfer chamber 32. This makes it possible to shorten the time required for switching the internal pressure of the load lock chamber 31 as compared with the time required for switching the internal pressure of the surface modifying apparatus 33.

Furthermore, the modifying transfer device 32 a is not disposed in the load lock chamber 31 but is disposed adjacent to the load lock chamber 31. Thus, the load lock chamber 31 can be reduced in size as compared with the case where the modifying transfer device 32 a is disposed in the load lock chamber 31. As a result, it is possible to further shorten the time required for switching the internal pressure of the load lock chamber 31.

The surface hydrophilizing apparatus 34 (see FIG. 2) hydrophilizes and cleans the bonding surfaces W1 j and W2 j of the upper wafer W1 and the lower wafer W2 by a hydrophilization treatment liquid such as, for example, pure water or the like. In the surface hydrophilizing apparatus 34, for example, pure water is supplied onto the upper wafer W1 or the lower wafer W2 while rotating the upper wafer W1 or the lower wafer W2 held by a spin chuck. As a result, the pure water supplied onto the upper wafer W1 or the lower wafer W2 diffuses on the bonding surface W1 j or W2 j of the upper wafer W1 or the lower wafer W2, whereby the bonding surface W1 j or W2 j is made hydrophilic.

As shown in FIG. 2, in the first processing block G1, the load lock chamber 31, the transfer chamber 32, the surface modifying apparatus 33 and the surface hydrophilizing apparatus 34 are disposed in a stacked state. More specifically, for example, in the first processing block G1, the load lock chamber 31, the transfer chamber 32 and the surface modifying apparatus 33 are disposed in the lower stage on the Z axis negative direction side, while the surface hydrophilizing apparatus 34 is disposed in the upper stage on the Z axis positive direction side.

As described above, in this embodiment, the load lock chamber 31, the transfer chamber 32 and the surface modifying apparatus 33 are disposed below the surface hydrophilizing apparatus 34. Thus, for example, the vacuum pumps 31 c, 32 c and 33 c and the suction pipes 31 b, 32 b and 33 b connected to the load lock chamber 31, the transfer chamber 32 and the surface modifying apparatus 33 can be collectively disposed below the bonding system 1. This makes it possible to downsize the entire system.

Furthermore, the vacuum pumps 31 c, 32 c and 33 c are disposed in the vicinity of the load lock chamber 31, the transfer chamber 32 and the surface modifying apparatus 33. It is therefore possible to shorten the suction pipes 31 b, 32 b and 33 b, eventually minimizing the time required for depressurization.

The arrangement positions of the load lock chamber 31, the surface modifying apparatus 33 and the surface hydrophilizing apparatus 34 shown in FIG. 1 are illustrative and not limitative. That is to say, the load lock chamber 31 and the surface modifying apparatus 33 may be disposed above the surface hydrophilizing apparatus 34. Furthermore, for example, the load lock chamber 31 and the surface modifying apparatus 33 may be disposed in the second processing block G2 or the third processing block G3. Moreover, for example, a new station may be provided at a position on the X axis positive direction side of the processing station 3 or between the loading/unloading station 2 and the processing station 3. The load lock chamber 31 and the surface modifying apparatus 33 may be disposed in the new station.

In the second processing block G2, a bonding apparatus 41, a substrate temperature control device 42 and an exhaust port 43 are disposed. The bonding apparatus 41 is located at a position closest to the loading/unloading station 2 in the second processing block G2. The substrate temperature control device 42 is disposed adjacent to the bonding apparatus 41 on the X axis positive direction side thereof. The substrate temperature control device 42 is disposed adjacent to the exhaust port 43 on the X axis negative direction side thereof.

The bonding apparatus 41 bonds the hydrophilized upper wafer W1 and the hydrophilized lower wafer W2 by an intermolecular force. The detailed configuration of the bonding apparatus 41 will be described later with reference to FIGS. 10 to 16H.

The substrate temperature control device 42 controls the temperature of the upper wafer W1 before bonding and the temperature of the lower wafer W2 before bonding, respectively. The detailed configuration of the substrate temperature control device 42 will be described later with reference to FIG. 7.

The exhaust port 43 discharges a temperature control gas (hereinafter referred to as “temperature control air”). That is to say, although not shown in the drawings, the processing station 3 is provided with an air supply port which is disposed at an appropriate position such as, for example, a ceiling portion on the side of the loading/unloading station 2 or the like so as to supply the temperature control air. The exhaust port 43 is configured to discharge the temperature control air supplied from the air supply port and passing through the processing station 3 to the outside of the processing station 3.

Therefore, in the processing station 3, the bonding apparatus 41, the substrate temperature control device 42 and the exhaust port 43 are disposed in this order along the flow direction of the temperature control air (the X axis positive direction). In other words, the substrate temperature control device 42 is disposed on the downstream side of the bonding apparatus 41 in the flow direction of the temperature control air.

The arrangement position of the exhaust port 43 is not limited to the example shown in the drawing. The exhaust port 43 may be disposed at other positions, for example, in the vicinity of the load lock chamber 31 or in the vicinity of the transfer region 60. Furthermore, the position of the air supply port is not limited to the one described above. The air supply port may be disposed at other positions such as a floor portion or a wall portion of the processing station 3.

As shown in FIG. 2, in the third processing block G3, a position adjusting device 51, transitions 53 and 54, and an inverting transition 55 are stacked and arranged sequentially from the upper side. The arrangement locations of the respective devices in the third processing block G3 are merely illustrative and not limitative.

FIG. 4 is a schematic side view showing a configuration of the position adjusting device 51. The position adjusting device 51 adjusts the horizontal orientations of the upper wafer W1 and the lower wafer W2. As shown in FIG. 4, the position adjusting device 51 includes a base 51 a, a holding part 51 b configured to suck, hold and rotate the upper wafer W1 and the lower wafer W2, a detecting part 51 c configured to detect a position of a notch portion of each of the upper wafer W1 and the lower wafer W2, and a base inverting part 51 d configured to invert the base 51 a.

In the position adjusting device 51, the position of the notch portion of each of the upper wafer W1 and the lower wafer W2 is detected by the detecting part 51 c while rotating the upper wafer W1 and the lower wafer W2 sucked and held by the holding part 51 b, whereby the horizontal orientations of the upper wafer W1 and the lower wafer W2 are adjusted by adjusting the positions of the notch portions.

In the detecting part 51 c, for example, a camera (not shown) may be provided so as to capture images of the peripheral edges of the upper wafer W1 and the lower wafer W2. For example, the detecting part 51 c captures an image of the peripheral edge of the upper wafer W1 or the like while rotating the upper wafer W1 or the like held by the holding part 51 b by one rotation, and plots the peripheral edge of the upper wafer W1 or the like based on the captured image. The detecting part 51 c may detect the radius of the upper wafer W1 and the lower wafer W2 based on the information on the peripheral edge of the upper wafer W1 or the like thus plotted.

In this manner, the position adjusting device 51 also functions as a radius detecting device for detecting the radius of the upper wafer W1 and the lower wafer W2. In the above description, the radius of the upper wafer W1 or the like is detected by the position adjusting device 51. However, the present disclosure is not limited thereto. For example, identification information (ID) indicating the radius or the like may be attached to the upper wafer W1 or the like. The radius may be detected by reading such identification information.

The base inverting part 51 d includes, for example, a motor and the like. The base inverting part 51 d is connected to the base 51 a and is configured to invert the base 51 a for each upper wafer W1 held by the holding part 51 b. Thus, the front and back surfaces of the upper wafer W1 held by the holding part 51 b are inverted. Accordingly, for example, the upper wafer W1 whose horizontal orientation is adjusted comes into a state in which the bonding surface W1 j serves as a lower surface (see FIG. 2) by the above-described inversion. In this state, the upper wafer W1 is unloaded from the position adjusting device 51. The upper wafer W1 and the lower wafer W2 unloaded from the position adjusting device 51 are transferred to the substrate temperature control device 42 and are temperature-controlled.

Returning to the description of FIG. 2, the upper wafer W1 transferred by the transfer device 22 or the transfer device 61 is temporarily mounted on the transition 53. Furthermore, the lower wafer W2 or the laminated wafer T transferred by the transfer device 22 or the transfer device 61 is temporarily mounted on the transition 54.

The inverting transition 55 is a device configured to temporarily hold the upper wafer W1 or the lower wafer W2 not bonded in the bonding apparatus 41 for a certain reason and returned from the bonding apparatus 41 in a state in which the bonding surface W1 j or W2 j serves as a lower surface. The inverting transition 55 is an example of a substrate transfer device.

FIG. 5A is a schematic plan view showing the configuration of the inverting transition 55, and FIG. 5B is a schematic side view showing the configuration of the inverting transition 55. As shown in FIG. 5B, the inverting transition 55 includes a holding part 56 and an inverting mechanism 57. The holding part 56 holds, on the side of a lower surface 56 a 1 thereof, the upper wafer W1 or the lower wafer W2 having the bonding surface W1 j or W2 j as a lower surface.

Specifically, the holding part 56 is provided with a suction portion 56 a 2 on the side of a lower surface 56 a 1 thereof. A vacuum pump 56 a 4 is connected to the suction portion 56 a 2 via a suction pipe 56 a 3. Therefore, the lower surface 56 a 1 of the holding part 56 holds the upper wafer W1 or the lower wafer W2 through vacuum suction by the operation of the vacuum pump 56 a 4. As a result, the holding part 56 can reliably hold the upper wafer W1 and the like.

The holding part 56 is further provided with a suction portion 56 b 2 on the side of an upper surface 56 b 1 thereof. A vacuum pump 56 b 4 is connected to the suction portion 56 b 2 via a suction pipe 56 b 3. Therefore, the upper surface 56 b 1 of the holding part 56 is configured to be able to suck the upper wafer W1 or the like by the operation of the vacuum pump 56 b 4.

The inverting mechanism 57 includes, for example, a motor and the like. The inverting mechanism 57 is connected to the holding part 56 and is configured to invert the front and back surfaces of the upper wafer W1 or the like held by the holding part 56. The inverting mechanism 57 of the inverting transition 55 inverts the upper wafer W1 not bonded by the bonding apparatus 41.

Specifically, for example, there may be a case where, for some reason, the upper wafer W1 and the lower wafer W2 are not bonded in the bonding apparatus 41, and the upper wafer W1 having the bonding surface W1 j as a lower surface is returned to the third processing block G3. In this case, the upper wafer W1 having the bonding surface W1 j as a lower surface is transferred to the inverting transition 55 by the transfer device 61 and is held by the suction portion 56 a 2 from the side of the non-bonding surface W1 n. Next, the inverting mechanism 57 inverts the holding part 56 so that the upper wafer W1 is brought into a state in which the bonding surface W1 j serves as an upper surface. The upper wafer W1 in such a state is indicated by imaginary lines in FIGS. 5A and 5B.

Thus, for example, the upper wafer W1 returned without being bonded in the bonding apparatus 41 can be brought into the same state as when the upper wafer W1 is accommodated in the cassette C1, namely a state in which the bonding surface W1 j serves as an upper surface as indicated by an imaginary line in FIG. 5B. In this manner, in the inverting transition 55, for example, it is possible to easily invert the front and back surfaces of the upper wafer W1 having the bonding surface W1 j as a lower surface. The upper wafer W1 having the bonding surface W1 j as an upper surface can be transferred to the cassette C1 by the transfer device 22 and can be accommodated in the cassette C1 as it is.

Next, the configuration of the transfer device 61 will be described with reference to FIGS. 6A and 6B. FIG. 6A is a schematic plan view showing the configuration of the transfer device 61, and FIG. 6B is a schematic side view showing the configuration of the transfer device 61.

As shown in FIG. 6B, the transfer device 61 includes a first holding part 62 a, a second holding part 62 b provided to face the lower side of the first holding part 62 a, and a first driving part 64. As the first holding part 62 a and the second holding part 62 b, it may be possible to use a bifurcated fork whose lateral width is smaller than the diameter of the upper wafer W1 or the like. However, the present disclosure is not limited thereto.

In this embodiment, the first holding part 62 a is used for holding the upper wafer W1 having the bonding surface W1 j as a lower surface. On the other hand, the second holding part 62 b is used for holding the lower wafer W2 having the bonding surface W2 j as an upper surface, the upper wafer W1 having the bonding surface W1 j as an upper surface, the laminated wafer T, and the like. The types of the respective wafers held by the first holding part 62 a and the second holding part 62 b are illustrative and not limitative. For example, the first holding part 62 a may hold the laminated wafer T.

In the first holding part 62 a, a plurality of suction portions 62 a 2 (indicated by broken lines in FIG. 6A) is provided on the side of a lower surface 62 a 1 thereof. A vacuum pump 62 a 4 is connected to the suction portions 62 a 2 via a suction pipe 62 a 3. Therefore, the first holding part 62 a holds the upper wafer W1 through vacuum suction by the operation of the vacuum pump 62 a 4. Specifically, the first holding part 62 a holds the upper wafer W1 having the bonding surface W1 j as a lower surface from the side of the non-bonding surface W1 n (upper surface side) by vacuum suction.

The second holding part 62 b includes a plurality of suction portions (not visible in FIGS. 6A and 6B) on the side of an upper surface 62 b 1. A vacuum pump 62 b 4 is connected to the suction portions via a suction pipe 62 b 3 (see FIG. 6B). Therefore, the second holding part 62 b holds the lower wafer W2 or the like through vacuum suction by the operation of the vacuum pump 62 b 4.

Specifically, the second holding part 62 b holds the lower wafer W2 having the bonding surface W2 j as an upper surface through vacuum suction from the side of the non-bonding surface W2 n (lower surface side) by allowing the lower wafer W2 to face the upper wafer W1. Although not shown, the second holding part 62 b also holds the laminated wafer T by vacuum suction as described above.

In this manner, the first holding part 62 a holds the upper wafer W1 by vacuum suction, and the second holding part 62 b holds the lower wafer W2 by vacuum suction. Thus, the first and second holding parts 62 a and 62 b can reliably hold the upper wafer W1 and the lower wafer W2.

The first driving part 64 is connected to the first holding part 62 a and the second holding part 62 b. The first driving part 64 drives the first holding part 62 a and the second holding part 62 b together and integrally moves the first holding part 62 a and the second holding part 62 b in the vertical direction and the horizontal direction and about the vertical axis with respect to a base 65. Although not shown, the first driving part 64 includes a drive source such as a motor or the like and a power transmission mechanism such as a belt or the like.

By configuring the transfer device 61 as described above, it is possible to downsize the transfer device 61. That is to say, for example, if driving parts are respectively connected to the first holding part 62 a and the second holding part 62 b, the number of driving parts is two and the transfer device 61 is increased in size. However, in the transfer device 61 according to the present embodiment, the first and second holding parts 62 a and 62 b are driven together by one first driving part 64. This makes it possible to reduce the size of the transfer device 61.

When transferring the upper wafer W1 and the lower wafer W2 to the bonding apparatus 41, the transfer device 61 holds the upper wafer W1 with the first holding part 62 a and holds the lower wafer W2 with the second holding part 62 b, thereby transferring the upper wafer W1 and the lower wafer W2 together.

More specifically, the first holding part 62 a holds the upper wafer W1 having the bonding surface W1 j as a lower surface from the upper surface side, and the second holding part 62 b holds the lower wafer W2 having the bonding surface W2 j as an upper surface from the lower surface side by allowing the lower wafer W2 to face the upper wafer W1.

Thus, in the bonding apparatus 41, the upper wafer W1 and the lower wafer W2 are transferred in the same orientation as that available when performing a bonding process. Therefore, in the bonding apparatus 41, it is not necessary to perform, for example, a process of inverting the orientation of the upper wafer W1. As a result, it is possible to shorten the time required for performing the bonding process in the bonding apparatus 41. In this embodiment, the second holding part 62 b transfers the lower wafer W2 to the bonding apparatus 41 while holding the lower wafer W2 in a state in which the center thereof is shifted from the center of the upper wafer W1. This will be described later with reference to FIGS. 8A to 9.

The transfer device 61 further includes a plurality of (four, in this example) position detecting parts 70 a to 70 d. For example, the position detecting parts 70 a to 70 d are fixed to the base 65. The position detecting parts 70 a to 70 d detect the positions of the peripheral edges of the upper wafer W1 and the lower wafer W2 held by the first holding part 62 a and the second holding part 62 b, at different locations, respectively.

More specifically, each of the position detecting parts 70 a to 70 d includes a light projecting part 71 and a light receiving part 72. The light projecting part 71 and the light receiving part 72 are disposed at positions where the light projecting part 71 and the light receiving part 72 sandwich the upper wafer W1 and the lower wafer W2 held by the first holding part 62 a and the second holding part 62 b from above and below. That is, the position detecting parts 70 a to 70 d are disposed perpendicularly to the surfaces (for example, the bonding surfaces W j and W2 j and the non-bonding surfaces Win and W2 n) of the upper wafer W1 and the lower wafer W2 held by the first holding part 62 a and the second holding part 62 b

The arrangement of the light projecting part 71 and the light receiving part 72 is not limited to the example described above. For example, the light projecting part 71 may be disposed above the upper wafer W1 or the like and the light receiving part 72 may be disposed below the upper wafer W1 or the like. As the light receiving part 72, it may be possible to use a line sensor in which a plurality of light receiving elements is linearly arranged. However, the present disclosure is not limited thereto.

The light receiving part 72 receives the light irradiated from the light projecting part 71 using the light receiving elements. However, when the upper wafer W1 or the like exists between the light projecting part 71 and the light receiving part 72, the light is partially blocked by the upper wafer W1 or the like.

As a result, in the light receiving part 72, a difference occurs in the amount of received light between the light receiving element that receives light and the light receiving element that does not receive light. The position detecting parts 70 a to 70 d detect the position of the peripheral edge of the upper wafer W1 or the like based on the difference in the amount of received light. The position detecting parts 70 a to 70 d send a signal indicating the detection result to a control device 100 (see FIG. 1) which will be described later. A process for detecting the position of the peripheral edge of the upper wafer W1 or the like by the position detecting parts 70 a to 70 d will be described later.

Returning to the description of FIG. 1, the bonding system 1 includes a control device 100. The control device 100 controls the operation of the bonding system 1. The control device 100 is, for example, a computer, and includes a control part and a memory unit (not shown). A program for controlling various processes such as a bonding process and the like, data used in various processes, and the like are stored in the memory part. The control part controls the operation of the bonding system 1 by reading out and executing the program or the like stored in the memory part.

Such a program may be recorded in a computer-readable recording medium and may be installed in the memory part of the control device 100 from the recording medium. Examples of the computer-readable recording medium include a hard disk (HD), a flexible disk (FD), a compact disk (CD), a magneto-optical disk (MO), a memory card, and the like.

Now, the substrate temperature control device 42 will be described in detail with reference to FIG. 7. FIG. 7 is a schematic side view showing the configuration of the substrate temperature control device 42.

The upper wafer W1 having the bonding surface W1 j as a lower surface and the lower wafer W2 having the bonding surface W2 j as an upper surface are transferred to the substrate temperature control device 42 by the transfer device 61. The substrate temperature control device 42 controls the temperature of each of the upper wafer W1 and the lower wafer. Specifically, as shown in FIG. 7, the substrate temperature control device 42 includes a first temperature control holding plate 42 a and a second temperature control holding plate 42 b. The first temperature control holding plate 42 a is an example of a first holding plate, and the second temperature control holding plate 42 b is an example of a second holding plate.

The first temperature control holding plate 42 a holds the upper wafer W1 before bonding, more specifically, the upper wafer W1 after hydrophilizing and before bonding. Specifically, the first temperature control holding plate 42 a is provided with a plurality of holding pins 42 a 2 on a holding surface 42 a 1 for holding the upper wafer W1. The holding pins 42 a 2 are configured to be movable upward and downward with respect to the holding surface 42 a 1 of the first temperature control holding plate 42 a.

A vacuum pump 42 a 4 is connected to the holding pins 42 a 2 via a suction pipe 42 a 3. Therefore, the first temperature control holding plate 42 a holds the upper wafer W1 through vacuum suction by the operation of the vacuum pump 42 a 4. It is assumed that the non-bonding surface W1 n of the upper wafer W1 is sucked and held by the holding pins 42 a 2 of the first temperature control holding plate 42 a.

Furthermore, a first temperature control mechanism 42 a 5 is built in the first temperature control holding plate 42 a. For example, a temperature-controlled coolant such as cooling water or the like is circulated through the first temperature control mechanism 42 a 5. Accordingly, the first temperature control holding plate 42 a controls the temperature of the upper wafer W1 by adjusting the cooling temperature of the first temperature control mechanism 42 a 5 or by raising and lowering the holding pins 42 a 2 to adjust the spaced-apart distance between the holding pins 42 a 2 and the upper wafer W1.

As shown in FIG. 7, the second temperature control holding plate 42 b is disposed to hold the lower wafer W2 in a state in which the center thereof is shifted from the center of the upper wafer W1 held by the first temperature control holding plate 42 a.

Specifically, the second temperature control holding plate 42 b is disposed so that a holding surface 42 b 1 thereof faces the holding surface 42 a 1 of the first temperature control holding plate 42 a. The second temperature control holding plate 42 b holds the lower wafer W2 before bonding, specifically the lower wafer W2 after hydrophilizing and before bonding, from the lower surface side so that the lower wafer W2 faces the upper wafer W1.

At this time, as shown in FIG. 7, in the lower wafer W2 held by the second temperature control holding plate 42 b, the center W2 c thereof is shifted from the center W1 c of the upper wafer W1 by a predetermined distance E in the Y axis positive direction.

The predetermined distance E is, for example, about several mm to several tens of mm, but is not limited thereto. Further, in the illustrated example, the lower wafer W2 held by the second temperature control holding plate 42 b is positioned so as to be shifted from the upper wafer W1 in the Y axis direction. However, this is illustrative and not limitative. For example, the lower wafer W2 may be positioned so as to be shifted from the upper wafer W1 in the X axis direction or other directions.

Furthermore, the second temperature control holding plate 42 b is provided with a plurality of holding pins 42 b 2 on the holding surface 42 b 1 for holding the lower wafer W2. The holding pins 42 b 2 are configured to be movable upward and downward with respect to the holding surface 42 b 1 of the second temperature control holding plate 42 b.

A vacuum pump 42 b 4 is connected to the holding pins 42 b 2 via a suction pipe 42 b 3. Therefore, the second temperature control holding plate 42 b holds the lower wafer W2 using vacuum suction from the vacuum pump 42 b 4.

Thus, the second temperature control holding plate 42 b can reliably hold the lower wafer W2. That is to say, for example, in the second temperature control holding plate 42 b, when the holding pins 42 b 2 hold the lower wafer W2 by mounting instead of vacuum suction, a stopper member for preventing the lower wafer W2 from sliding down is provided on the holding surface 42 b 1 at a position corresponding to the radial size of the lower wafer W2. However, in the second temperature control holding plate 42 b according to this embodiment, vacuum suction is performed as described above. Therefore, there is no need to use a stopper member to prevent slippage. It is possible to reliably hold the lower wafer W2 regardless of the radial size of the lower wafer W2.

It is assumed that the non-bonding surface W2 n of the lower wafer W2 is sucked and held by the holding pins 42 b 2. In the above description, the second temperature control holding plate 42 b holds the lower wafer W2 by suction. However, the present disclosure is not limited thereto. For example, the vacuum pump 42 b 4 and the suction pipe 42 b 3 may be removed and the lower wafer W2 may be held by mounting.

A second temperature control mechanism 42 b 5 is built in the second temperature control holding plate 42 b. For example, a coolant is circulated through the second temperature control mechanism 42 b 5. A plurality of proximity pins 42 b 7 capable of supporting the lower wafer W2 is provided on the holding surface 42 b 1 of the second temperature control holding plate 42 b.

In the second temperature control holding plate 42 b configured as above, the transferred lower wafer W2 is held by the holding pins 42 b 2. Subsequently, the holding pins 42 b 2 are moved down until the tips of the holding pins 42 b 2 are positioned lower than the proximity pins 42 b 7. As a result, the lower wafer W2 is supported by the proximity pins 42 b 7. An appropriate gap is secured between the lower wafer W2 and the holding surface 42 b 1 of the second temperature control holding plate 42 b. In this manner, the second temperature control holding plate 42 b adjusts the temperature of the lower wafer W2 in a state in which an appropriate spaced-apart distance between the second temperature control holding plate 42 b and the lower wafer W2 is maintained.

Although the proximity pins 42 b 7 are used in the second temperature control holding plate 42 b, the present disclosure is not limited thereto. For example, the proximity pins 42 b 7 may be removed and the temperature of the lower wafer W2 may be adjusted by lowering the holding pins 42 b 2 to a position where the holding pins 42 b 2 is appropriately spaced apart from the lower wafer W2, and maintaining the holding pins 42 b 2 at the position.

As the first and second temperature control mechanisms 42 a 5 and 42 b 5, it may be possible to use cooling jackets or the like. However, the present disclosure is not limited thereto. For example, other types of temperature control mechanisms such as a heater and the like may be used.

The substrate temperature control device 42 configured as above performs temperature control so that the lower wafer W2 before bonding has a higher temperature than the temperature of the upper wafer W1 before bonding. As a result, it is possible to suppress scaling.

Scaling is a phenomenon that, for example, in the bonded laminated wafer T, a positional deviation occurs in the horizontal direction at the peripheral edges of the upper wafer W1 and the lower wafer W2, even if the central portions of the upper wafer W1 and the lower wafer W2 are aligned with each other. This phenomenon occurs because, as will be described later, when bonding the upper wafer W1 and the lower wafer W2, the central portion W1 a of the upper wafer W1 is lowered toward the central portion W2 a of the lower wafer W2 by a pushing member 250 (see FIG. 16D), whereby the upper wafer W1 is warped and stretched downward in a convex shape.

Therefore, in the substrate temperature control device 42 according to this embodiment, the temperature control is performed so that the lower wafer W2 before bonding has a higher temperature than the temperature of the upper wafer W1 before bonding, thereby expanding the lower wafer W2. Thus, it is possible to effectively suppress the horizontal positional deviation (scaling) of the peripheral edges of the upper wafer W1 and the lower wafer W2.

In the above description, the substrate temperature control device 42 performs temperature control so that the lower wafer W2 before bonding has a higher temperature than the temperature of the upper wafer W1 before bonding. However, this is illustrative and not limitative. For example, the lower wafer W2 and the upper wafer W1 may have the same temperature.

In the above description, the substrate temperature control device 42 controls the temperatures of both the upper wafer W1 and the lower wafer W2. However, the present disclosure is not limited thereto. The temperature of any one of the upper wafer W1 and the lower wafer W2 may be controlled.

As described above, the substrate temperature control device 42 is disposed on the downstream side of the bonding apparatus 41 in the flow direction of the temperature control air (see FIG. 1). Accordingly, the temperature environments around the substrate temperature control device 42 and the bonding apparatus 41 are similar. Thus, when the upper wafer W1 and the lower wafer W2 whose temperatures have been controlled by the substrate temperature control device 42 are transferred to the bonding apparatus 41, it is possible to limit influences such as a decrease in the wafer temperature due to the surrounding temperature. Consequently, it is possible to easily manage the temperatures of the upper wafer W1 and the lower wafer W2.

In addition, for example, the transfer device of the related art is configured to receive the upper wafer W1 and the lower wafer W2 one at a time from the substrate temperature control device and to transfer the upper wafer W1 and the lower wafer W2 to the bonding apparatus. Therefore, it takes time to transfer a set of the first and second substrates to the bonding apparatus.

Thus, in this embodiment, the substrate temperature control device 42 and the transfer device 61 are configured as described above. Therefore, the transfer device 61 can receive two upper and lower wafers W1 and W2 together from the substrate temperature control device 42. As a result, in the bonding system 1, the processing time for transferring the upper wafer W1 and the lower wafer W2 to the bonding apparatus 41 can be shortened as compared with the case where the transfer device 61 receives the upper wafer W1 and the lower wafer W2 one at a time from the substrate temperature control device 42.

Now, an operation in which the above-described transfer device 61 receives two upper and lower wafers W1 and W2 together from the substrate temperature control device 42 will be described with reference to FIGS. 8A to 8F. FIGS. 8A to 8F are views for explaining the operation of the transfer device 61 and the substrate temperature control device 42. In FIGS. 8A to 8F, the illustration of components other than the components necessary for explanation may be omitted in some cases.

As shown in FIG. 8A, first, the lower wafer W2 before temperature control is transferred to the substrate temperature control device 42. More specifically, the lower wafer W2 that is sucked and held by the second holding part 62 b of the transfer device 61 is transferred to between the first temperature control holding plate 42 a and the second temperature control holding plate 42 b of the substrate temperature control device 42.

In the substrate temperature control device 42, the lower wafer W2 is sucked and held on the holding pins 42 b 2 by operating the vacuum pump 42 b 4 (see FIG. 7) after moving the holding pins 42 b 2 upward. Subsequently, the transfer device 61 stops the vacuum pump 62 b 4 (see FIG. 6B) to terminate the holding by suction. Then, the transfer device 61 is retracted from the substrate temperature control device 42.

Thereafter, as shown in FIG. 8B, the substrate temperature control device 42 moves the holding pins 42 b 2 downward. When the lower wafer W2 comes into contact with the proximity pins 42 b 7, the vacuum pump 42 b 4 is stopped to terminate the holding by suction. Subsequently, the holding pins 42 b 2 are moved down until the tips of the holding pins 42 b 2 become lower than the proximity pins 42 b 7. Thus, the lower wafer W2 is supported by the proximity pins 42 b 7. As a result, the temperature of the lower wafer W2 is controlled by the second temperature control mechanism 42 b 5.

Next, as shown in FIG. 8C, the upper wafer W1 before temperature control is transferred to the substrate temperature control device 42. Specifically, the upper wafer W1 sucked and held by the first holding part 62 a of the transfer device 61 is transferred between the first temperature control holding plate 42 a and the second temperature control holding plate 42 b of the substrate temperature control device 42.

In the substrate temperature control device 42, after the holding pins 42 a 2 are moved down, the upper wafer W1 is sucked and held on the holding pins 42 a 2 by operating the vacuum pump 42 a 4 (see FIG. 7). Then, the transfer device 61 stops the vacuum pump 62 a 4 (see FIG. 6B) to terminate the holding by suction. The transfer device 61 is retracted from the substrate temperature control device 42. Thereafter, as shown in FIG. 8D, the substrate temperature control device 42 moves the holding pins 42 a 2 upward and brings the upper wafer W1 close to the first temperature control holding plate 42 a, whereby the temperature of the upper wafer W1 is controlled by the first temperature control mechanism 42 a 5.

In the state shown in FIG. 8D, the center W2 c of the lower wafer W2 held by the second temperature control holding plate 42 b and the center W1 c of the upper wafer W1 held by the first temperature control holding plate 42 a are shifted from each other.

In the substrate temperature control device 42, as described above, the temperature of the lower wafer W2 is controlled to be higher than the temperature of the upper wafer W1. Therefore, the lower wafer W2 and the upper wafer W1 are transferred in the named order to secure enough time to raise the temperature of the lower wafer W2. The order in which the upper wafer W1 and the lower wafer W2 are transferred to the substrate temperature control device 42 is not limited thereto. For example, the upper wafer W and the lower wafer W2 may be transferred in the named order or may be transferred at the same time.

Next, the first and second holding parts 62 a and 62 b of the transfer device 61 receive the upper wafer W1 and the lower wafer W2 held and temperature-controlled by the first and second temperature control holding plates 42 a and 42 b, at the same time, from the first and second temperature control holding plates 42 a and 42 b, and hold the upper wafer W1 and the lower wafer W2 thus received.

Specifically, as shown in FIG. 8E, in the substrate temperature control device 42, the holding pins 42 a 2 are moved down to lower the upper wafer W1 to a position where the upper wafer W1 can be received by the first holding part 62 a. In the substrate temperature control device 42, the vacuum pump 42 b 4 (see FIG. 7) is operated while moving the holding pins 42 b 2 upward, so that the holding pins 42 b 2 suck and hold the lower wafer W2 supported by the proximity pins 42 b 7. Thereafter, the holding pins 42 b 2 are further moved upward to raise the lower wafer W2 to a position where the lower wafer W2 can be received by the second holding part 62 b.

Then, the first and second holding parts 62 a and 62 b of the transfer device 61 are moved between the first temperature control holding plate 42 a and the second temperature control holding plate 42 b to receive two upper and lower wafers W1 and W2 together. More specifically, the first holding part 62 a operates the vacuum pump 62 a 4 (see FIG. 6B) to suck the upper wafer W1 and the second holding part 62 b operates the vacuum pump 62 b 4 (see FIG. 6B) to suck the lower wafer W2, thereby receiving two upper and lower wafers W1 and W2 together. At this time, the second holding part 62 b holds the lower wafer W2 with the center W2 c thereof shifted from the center W1 c of the upper wafer W1.

Subsequently, the substrate temperature control device 42 stops the vacuum pumps 42 a 4 and 42 b 4 (see FIG. 7) to terminate the holding by suction. Thereafter, as shown in FIG. 8F, the first and second holding parts 62 a and 62 b of the transfer device 61 are retracted from the substrate temperature control device 42 and transfer the upper wafer W1 and the lower wafer W2 held thereon to the bonding apparatus 41. In addition, in the substrate temperature control device 42, the holding pins 42 a 2 are moved up and the holding pins 42 b 2 are moved down so that they return to the initial positions, respectively.

As described above, in this embodiment, the transfer device 61 receives the upper wafer W1 and the lower wafer W2 together from the substrate temperature control device 42 at the same time. Therefore, the processing time for transferring the upper wafer W1 and the lower wafer W2 to the bonding apparatus 41 can be shortened as compared with the case where the upper wafer W1 and the lower wafer W2 are received one at a time from the substrate temperature control device 42.

Subsequently, in the bonding system 1, both of the upper wafer W1 and the lower wafer W2 are transferred and delivered to the bonding apparatus 41 by the transfer device 61. At this time, in order for the transfer device 61 to deliver the upper wafer W1 and the lower wafer W2 to appropriate positions in the bonding apparatus 41, the position detecting parts 70 a to 70 d detect the positions of the upper wafer W1 and the lower wafer W2 held by the transfer device 61.

As described above, the position detecting parts 70 a to 70 d are disposed in a direction perpendicular to the surfaces of the upper wafer W1 and the lower wafer W2 held as above (see FIG. 6B). Therefore, for example, when the centers W1 c and W2 c of the upper wafer W1 and the lower wafer W2 are at the same position in a plan view, the lower wafer W2 is hidden by the upper wafer W1. Thus, the position detecting parts 70 a to 70 d cannot detect the position of the lower wafer W2.

Therefore, in this embodiment, as described above, the second holding part 62 b holds the lower wafer W2 in a state in which the center W2 c thereof is shifted from the center W1 c of the upper wafer W1. As a result, the position detecting parts 70 a to 70 d can detect the positions of the upper wafer W1 and the lower wafer W2.

FIG. 9 is a view for explaining the detection of the positions of the upper wafer W1 and the lower wafer W2 by the position detecting parts 70 a to 70 d. Furthermore, FIG. 9 is a schematic plan view of the transfer device 61.

As shown in FIG. 9, the lower wafer W2 is held in a state in which the center W2 c thereof is shifted from the center W1 c of the upper wafer W1. Therefore, in the lower wafer W2, at least a portion of the peripheral edge of the lower wafer W2 is exposed from the upper wafer W1 in a plan view.

The fact that the center W2 c of the lower wafer W2 is shifted from the center W1 c of the upper wafer W1 in the Y axis positive direction can be noted from the positional relationship between the first temperature control holding plate 42 a and the second temperature control holding plate 42 b. Therefore, among the position detecting parts 70 a to 70 d, the position detecting parts 70 a and 70 c arranged in the Y axis positive direction detect the position (points Pa2 and Pb2) of the peripheral edge of the lower wafer W2, and the position detecting parts 70 b and 70 d arranged in the Y axis negative direction detect the position (points Pa1 and Pb1) of the peripheral edge of the upper wafer W1.

In the position detecting parts 70 a and 70 c, the position of the peripheral edge at the points Pa2 and Pb2 are acquired with respect to the lower wafer W2. Thus, the position of the held lower wafer W2 is detected on the basis of the information on the position of the peripheral edge and the radius of the lower wafer W2 already detected. Similarly, in the position detecting parts 70 b and 70 d, the position of the peripheral edge at the points Pa1 and Pb1 are acquired with respect to the upper wafer W1. Thus, the position of the held upper wafer W1 is detected on the basis of the information on the position of the peripheral edge and the radius of the upper wafer W1 already detected.

As described above, the position detecting parts 70 a to 70 d detect the peripheral edge of the upper wafer W1 and detect the peripheral edge of the lower wafer W2 exposed from the upper wafer W1 in a plan view due to the shift of the center W2 c from the center W1 c of the upper wafer W1. The position detecting parts 70 a to 70 d detect the positions of the upper wafer W1 and the lower wafer W2 based on the detected peripheral edge of the upper wafer W1 and the detected portion of the peripheral edge of the lower wafer W2.

As a result, in this embodiment, even when the transfer device 61 receives two upper and lower wafers W1 and W2 from the substrate temperature control device 42, it is possible to accurately detect the positions of the upper wafer W1 and the lower wafer W2 held by the transfer device 61. Consequently, it is possible to deliver the upper wafer W1 and the lower wafer W2 to the bonding apparatus 41 at appropriate positions.

As described above, in the substrate temperature control device 42, the second temperature control holding plate 42 b is disposed to hold the lower wafer W2 in a state in which the center W2 c thereof is shifted from the center W1 c of the upper wafer W1 held by the first temperature control holding plate 42 a. Thus, the transfer device 61 can easily receive the upper wafer W1 and the lower wafer W2 from the substrate temperature control device 42 in a state in which the centers W1 c and W2 c are shifted from each other.

<2. Configuration of Bonding Apparatus>

Next, the configuration of the bonding apparatus 41 will be described with reference to FIGS. 10 to 15. FIG. 10 is a schematic plan view showing the configuration of the bonding apparatus 41, and FIG. 11 is a schematic side view thereof. FIG. 12 is a schematic side view showing the internal configuration of the bonding apparatus 41.

As shown in FIG. 10, the bonding apparatus 41 includes a processing container 190 capable of hermetically sealing the interior thereof. A loading/unloading port 191 for the upper wafer W1, the lower wafer W2 and the laminated wafer T is formed on the side surface of the processing container 190 on the side of the transfer region 60. An opening/closing shutter 192 is provided at the loading/unloading port 191.

As shown in FIG. 11, an upper chuck 230 and a lower chuck 231 are provided inside the processing container 190. The upper chuck 230 sucks and holds the upper wafer W1 from above. The lower chuck 231 is provided below the upper chuck 230 to suck and hold the lower wafer W2 from below.

As shown in FIG. 11, the upper chuck 230 is supported by a support member 280 provided on the ceiling surface of the processing container 190.

In the support member 280, an upper imaging part 281 (see FIG. 12) is provided for capturing an image of the bonding surface W2 j of the lower wafer W2 held by the lower chuck 231. The upper imaging part 281 is provided adjacent to the upper chuck 230.

As shown in FIGS. 10, 11 and 12, the lower chuck 231 is supported by a first lower chuck moving part 290 provided below the lower chuck 231. The first lower chuck moving part 290 moves the lower chuck 231 in the horizontal direction (Y axis direction) as described later. Furthermore, the first lower chuck moving part 290 is configured to be able to move the lower chuck 231 in the vertical direction and to be able to rotate the lower chuck 231 about the vertical axis.

In the first lower chuck moving part 290, there is provided a lower imaging part 291 for capturing an image of the bonding surface W1 j of the upper wafer W1 held by the upper chuck 230. The lower imaging part 291 is provided adjacent to the lower chuck 231.

As shown in FIGS. 10, 11 and 12, the first lower chuck moving part 290 is attached to a pair of rails 295 and 295 provided on the lower surface side of the first lower chuck moving part 290 and extending in the horizontal direction (Y axis direction). The first lower chuck moving part 290 is configured to be movable along the rails 295 and 295.

The rails 295 and 295 are provided in the second lower chuck moving part 296. The second lower chuck moving part 296 is attached to a pair of rails 297 and 297 provided on the lower surface side of the second lower chuck moving part 296 and extending in the horizontal direction (X axis direction). The second lower chuck moving part 296 is configured to be movable along the rails 297 and 297, namely to move the lower chuck 231 in the horizontal direction (X axis direction). The rails 297 and 297 are provided on a mounting table 298 provided on the bottom surface of the processing container 190.

Next, the configurations of the upper chuck 230 and the lower chuck 231 will be described with reference to FIGS. 13 to 15. FIG. 13 is a schematic side view showing the configurations of the upper chuck 230 and the lower chuck 231. FIG. 14 is a schematic plan view of the upper chuck 230 as viewed from below, and FIG. 15 is a schematic plan view of the lower chuck 231 as viewed from above.

As shown in FIG. 13, the upper chuck 230 is partitioned into a plurality of, for example, three regions 230 a, 230 b and 230 c. As shown in FIG. 14, these regions 230 a, 230 b and 230 c are provided in this order from the central portion of the upper chuck 230 toward the peripheral edge portion (outer peripheral portion) thereof. The region 230 a has a circular shape in a plan view, and the regions 230 b and 230 c have an annular shape in a plan view.

As shown in FIG. 13, suction pipes 240 a, 240 b and 240 c for sucking and holding the upper wafer W1 are provided independently in the respective regions 230 a. 230 b and 230 c. Different vacuum pumps 241 a. 241 b and 241 c are connected to the suction pipes 240 a, 240 b and 240 c, respectively. In this manner, the upper chuck 230 is configured so as to be able to set the vacuum drawing of the upper wafer W1 for each of the regions 230 a, 230 b and 230 c.

Further, the upper chuck 230 is provided with a plurality of holding pins 245 that can be moved up and down in the vertical direction. A vacuum pump 246 is connected to the holding pins 245. That is to say, the holding pins 245 can hold the upper wafer W1 through vacuum suction by the operation of the vacuum pump 246.

Accordingly, in the upper chuck 230, for example, the holding pins 245 suck and receive the upper wafer W1 in a state in which the holding pins 245 protrude from the holding surface. Thereafter, the holding pins 245 are moved upward to bring the upper wafer W1 into contact with the holding surface. Subsequently, in the upper chuck 230, the vacuum pumps 241 a, 241 b and 241 c are operated to suck and hold the upper wafer W1 in the regions 230 a, 230 b and 230 c as shown in FIG. 11.

A through-hole 243 penetrating the upper chuck 230 in the thickness direction is formed in the central portion of the upper chuck 230. The central portion of the upper chuck 230 corresponds to the central portion W1 a of the upper wafer W1 sucked and held by the upper chuck 230. A pushing pin 251 of a pushing member 250 to be described later is inserted into the through-hole 243.

On the upper surface of the upper chuck 230, a pushing member 250 for pushing the central portion of the upper wafer W1 is provided. The pushing member 250 has a cylinder structure and includes a pushing pin 251 and an outer cylinder 252 serving as a guide when the pushing pin 251 moves up and down. The pushing pin 251 can be vertically moved up and down through the through-hole 243 by, for example, a driving part (not shown) incorporating a motor therein. At the time of bonding the upper wafer W1 and the lower wafer W2 as described later, the pushing member 250 can press the central portion W1 a of the upper wafer W1 and the central portion W2 a of the lower wafer W2 against each other.

As shown in FIG. 15, the lower chuck 231 is partitioned into a plurality of, for example, two regions 231 a and 231 b. These regions 231 a and 231 b are provided in this order from the central portion of the lower chuck 231 toward the peripheral edge portion thereof. The region 231 a has a circular shape in a plan view, and the region 231 b has an annular shape in a plan view.

As shown in FIG. 13, suction pipes 260 a and 260 b for sucking and holding the lower wafer W2 are provided independently in the respective regions 231 a and 231 b. Different vacuum pumps 261 a and 261 b are connected to the suction pipes 260 a and 260 b, respectively. As described above, the lower chuck 231 is configured so as to be able to set the vacuum drawing of the lower wafer W2 for each of the regions 231 a and 231 b.

Further, the lower chuck 231 is provided with a plurality of holding pins 265 capable of moving up and down in the vertical direction. In the lower chuck 231, for example, the holding pins 265 mount and receive the lower wafer W2 in a state in which the holding pins 265 protrude from the holding surface. Thereafter, the holding pins 265 are moved down to bring the lower wafer W2 into contact with the holding surface. Subsequently, in the lower chuck 231, the vacuum pumps 261 a and 261 b are operated to suck and hold the lower wafer W2 in the respective regions 231 a and 231 b as shown in FIG. 13. In the above description, the holding pins 265 hold the lower wafer W2 by mounting. However, the present disclosure is not limited thereto. Similar to the holding pins 245 of the upper chuck 230, the holding pins 265 may hold the lower wafer W2 by suction.

In the peripheral edge portion of the lower chuck 231, stopper members 263 for preventing the upper wafer W1, the lower wafer W2 and the laminated wafer T from jumping out or slipping off from the lower chuck 231 are provided at a plurality of locations, for example, at five locations.

<3. Wafer Position Adjusting and Bonding Operation in Bonding Apparatus>

Next, the position adjustment of the upper wafer W1 and the lower wafer W2 and the bonding operation of the upper wafer W1 and the lower wafer W2 in the bonding apparatus 41 configured as above will be specifically described. FIGS. 16A to 16H are operation explanation views of the bonding apparatus 41.

It is assumed that the upper wafer W1 and the lower wafer W2 shown in FIGS. 16A to 16H have undergone the modifying process and the hydrophilizing process on the bonding surfaces W1 j and W2 j, respectively. In addition, it is assumed that the non-bonding surface Win of the upper wafer W1 is sucked and held by the upper chuck 230 and the non-bonding surface W2 n of the lower wafer W2 is sucked and held by the lower chuck 231.

Then, the upper wafer W1 held by the upper chuck 230 and the lower wafer W2 held by the lower chuck 231 are subjected to horizontal position adjustment.

As shown in FIG. 16A, a predetermined plurality of, for example, three reference points A1 to A3 are formed on the bonding surface W1 j of the upper wafer W1. Similarly, a predetermined plurality of, for example, three reference points B1 to B3 are formed on the bonding surface W2 j of the lower wafer W2. As the reference points A1 to A3 and B1 to B3, predetermined patterns formed on the upper wafer W1 and the lower wafer W2 are used, respectively. The number of reference points can be arbitrarily set.

First, as shown in FIG. 16A, the horizontal positions of the upper imaging part 281 and the lower imaging part 291 are adjusted. Specifically, the lower chuck 231 is horizontally moved by the first lower chuck moving part 290 and the second lower chuck moving part 296 so that the lower imaging part 291 is positioned substantially below the upper imaging part 281. Then, a common target X is confirmed by the upper imaging part 281 and the lower imaging part 291. The horizontal position of the lower imaging part 291 is finely adjusted so that the horizontal positions of the upper imaging part 281 and the lower imaging part 291 are aligned with each other.

Next, as shown in FIG. 16B, after the lower chuck 231 is moved vertically upward by the first lower chuck moving part 290, the horizontal positions of the upper chuck 230 and the lower chuck 231 are adjusted.

More specifically, while moving the lower chuck 231 in the horizontal direction by the first lower chuck moving part 290 and the second lower chuck moving part 296, the reference points B1 to B3 of the bonding surface W2 j of the lower wafer W2 are imaged using the upper imaging part 281. At the same time, while moving the lower chuck 231 in the horizontal direction, the reference points A1 to A3 of the bonding surface W1 j of the upper wafer W1 are sequentially imaged using the lower imaging part 291. FIG. 16B shows a state in which the reference point B1 of the lower wafer W2 is imaged by the upper imaging part 281 and the reference point A1 of the upper wafer W1 is imaged by the lower imaging part 291.

The captured image data is outputted to the control device 100. Based on the image data captured by the upper imaging part 281 and the image data captured by the lower imaging part 291, the control device 100 causes the first and second lower chuck moving parts 290 and 296 to adjust the horizontal position of the lower chuck 231 so that the reference points A1 to A3 of the upper wafer W1 and the reference points B1 to B3 of the lower wafer W2 are aligned with each other. Thus, the horizontal positions of the upper chuck 230 and the lower chuck 231 are adjusted, and the horizontal positions of the upper wafer W1 and the lower wafer W2 are adjusted.

Next, as shown in FIG. 16C, the lower chuck 231 is vertically moved upward by the first lower chuck moving part 290, whereby the vertical positions of the upper chuck 230 and the lower chuck 231 are adjusted, and the vertical positions of the upper wafer W1 held by the upper chuck 230 and the lower wafer W2 held by the lower chuck 231 are adjusted. At this time, the gap between the bonding surface W2 j of the lower wafer W2 and the bonding surface W1 j of the upper wafer W1 is a predetermined distance, for example, 80 μm to 200 μm.

With such a configuration, it is possible to adjust the horizontal positions and the vertical positions of the upper wafer W1 and the lower wafer W2 with high accuracy.

FIG. 16D shows the states of the upper chuck 230, the upper wafer W1, the lower chuck 231 and the lower wafer W2 after the adjustment of the horizontal positions and the vertical positions described above is completed. As shown in FIG. 16D, the upper wafer W1 is vacuum-drawn and held in all the regions 230 a, 230 b and 230 c of the upper chuck 230, and the lower wafer W2 is also vacuum-drawn and held in all the regions 231 a and 231 b of the lower chuck 231.

Next, a bonding process is performed in which the upper wafer W1 and the lower wafer W2 are bonded by an intermolecular force. Specifically, in the bonding process, the operation of the vacuum pump 241 a is stopped, and the vacuum drawing of the upper wafer W1 from the suction pipe 240 a in the region 230 a is stopped as shown in FIG. 16E. At this time, in the regions 230 b and 230 c, the upper wafer W1 is vacuum-drawn, sucked and held. Thereafter, by moving down the pushing pin 251 of the pushing member 250, the upper wafer W1 is lowered while pressing the central portion W1 a of the upper wafer W1. At this time, a load of, for example, 200 g, is applied to the pushing pin 251 such that the pushing pin 251 moves 70 μm in the absence of the upper wafer W1. Then, the central portion W1 a of the upper wafer W1 and the central portion W2 a of the lower wafer W2 are brought into contact with each other and pressed against each other by the pushing member 250.

As a result, bonding is started between the central portion W1 a of the pressed upper wafer W1 and the central portion W2 a of the lower wafer W2 (bold line portion in FIG. 16E). Since the bonding surface W1 j of the upper wafer W1 and the bonding surface W2 j of the lower wafer W2 are respectively modified, a van der Waals force (intermolecular force) is first generated between the bonding surfaces W1 j and W2 j. Thus, the bonding surfaces W1 j and W2 j are bonded together. Furthermore, since the bonding surface W1 j of the upper wafer W and the bonding surface W2 j of the lower wafer W2 are made hydrophilic, the hydrophilic groups between the bonding surfaces W1 j and W2 j are hydrogen-bonded. Thus, the bonding surfaces W1 j and W2 j are strongly bonded together.

Thereafter, as shown in FIG. 16F, the operation of the vacuum pump 241 b is stopped in a state in which the central portion W1 a of the upper wafer W1 and the central portion W2 a of the lower wafer W2 are pressed by the pushing member 250, whereby the vacuum drawing of the upper wafer W1 from the suction pipe 240 b in the region 230 b is stopped.

As a result, the upper wafer W1 held in the region 230 b drops onto the lower wafer W2. Thereafter, the operation of the vacuum pump 241 c is stopped, whereby the vacuum drawing of the upper wafer W1 from the suction pipe 240 c in the region 230 c is stopped. In this way, the vacuum drawing of the upper wafer W1 is stopped stepwise from the central portion W a of the upper wafer W1 toward the peripheral edge portion W1 b. Thus, the upper wafer W1 drops down and comes into contact with the lower wafer W2 in a stepwise manner. The aforementioned bonding due to the van der Waals force and the hydrogen bond between the bonding surfaces W1 j and W2 j is sequentially spread from the central portion W1 a toward the peripheral edge portion W1 b.

In this way, as shown in FIG. 16G, the bonding surface W1 j of the upper wafer W1 and the bonding surface W2 j of the lower wafer W2 make contact with each other over each of the surfaces in their entirety, whereby the upper wafer W1 and the lower wafer W2 are bonded together.

Thereafter, as shown in FIG. 16H, the pushing member 250 is moved up to the upper chuck 230. Further, in the lower chuck 231, the vacuum drawing of the lower wafer W2 from the suction pipes 260 a and 260 b is stopped, whereby the suction holding of the lower wafer W2 by the lower chuck 231 is canceled. As a result, the bonding process in the bonding apparatus 41 is completed.

<4. Specific Operation of Bonding System)>

Next, a specific operation of the bonding system 1 configured as above will be described with reference to FIG. 17. FIG. 17 is a flowchart showing a part of the processing procedure of the processes executed by the bonding system 1. The various processes shown in FIG. 17 are executed under the control of the control device 100.

First, a cassette C1 accommodating a plurality of upper wafers W1, a cassette C2 accommodating a plurality of lower wafers W2, and an empty cassette C3 are mounted on the predetermined mounting plates 11 of the loading/unloading station 2. Thereafter, the upper wafer W1 in the cassette C1 is taken out by the transfer device 22 and is transferred to the transition 53 of the third processing block G3 of the processing station 3.

Next, the upper wafer W1 is transferred to the load lock chamber 31 of the first processing block G1 by the transfer device 61 and is mounted on the transition 31 a 1, whereby the delivery of the upper wafer W1 is performed (step S101). Next, after the gate valve 36 a is closed, the vacuum pump 31 c is operated, whereby the load lock chamber 31 is depressurized into a depressurized atmosphere (step S102).

Next, the upper wafer W1 is transferred from the load lock chamber 31 to the surface modifying apparatus 33 by the modifying transfer device 32 a of the transfer chamber 32. In the surface modifying apparatus 33, an oxygen gas as a process gas is excited into plasma and ionized under a depressurized atmosphere. The oxygen ions are irradiated onto the bonding surface W1 j of the upper wafer W1, whereby the bonding surface W1 j is plasma-processed. As a result, the bonding surface W1 j of the upper wafer W1 is modified (step S103).

Next, the upper wafer W1 is transferred from the surface modifying apparatus 33 to the load lock chamber 31 by the modifying transfer device 32 a and is mounted on the transition 31 a 2. Then, the load lock chamber 31 is switched from the depressurized atmosphere to an atmospheric pressure atmosphere by opening the gate valve 36 a, and the upper wafer W1 is delivered (step S104). As described above, the load lock chamber 31 is set to an atmospheric pressure atmosphere. However, the transfer chamber 32 and the surface modifying apparatus 33 are kept in the depressurized atmosphere.

Next, the upper wafer W1 is transferred from the load lock chamber 31 to the surface hydrophilizing apparatus 34 by the transfer device 61. In the surface hydrophilizing apparatus 34, while rotating the upper wafer W1 held by the spin chuck, pure water is supplied onto the upper wafer W1. Then, the supplied pure water diffuses on the bonding surface W1 j of the upper wafer W1. A hydroxyl group (silanol group) adheres to the bonding surface W1 j of the upper wafer W1 modified in the surface modifying apparatus 33, whereby the bonding surface W1 j is rendered hydrophilic. In addition, the bonding surface W1 j of the upper wafer W1 is cleaned with the pure water (step S105).

Next, the hydrophilized upper wafer W1 is transferred to the position adjusting device 51 by the transfer device 61. Then, the horizontal orientation of the upper wafer is adjusted by the position adjusting device 51 (step S106).

Thereafter, the front and back surfaces of the upper wafer W1 are inverted by the base inverting part 51 d of the position adjusting device 51, whereby the bonding surface W1 j serves as a lower surface (step S107). Next, the upper wafer W1 having the bonding surface W1 j as a lower surface is transferred to the substrate temperature control device 42 by the transfer device 61. The upper wafer W1 is sucked and held by the first temperature control holding plate 42 a of the substrate temperature control device 42. As a result, the temperature of the upper wafer W1 is controlled (step S108).

The above-described processes of steps S101 to S106 and S108 are also performed with respect to the lower wafer W2. First, the lower wafer W2 in the cassette C2 is taken out by the transfer device 22 and is transferred to the transition 54 of the processing station 3.

Next, the lower wafer W2 is transferred to the load lock chamber 31 by the transfer device 61, whereby the delivery of the lower wafer W2 is performed (step S109). Subsequently, the load lock chamber 31 is depressurized into a depressurized atmosphere (step S110).

Next, the lower wafer W2 is transferred from the load lock chamber 31 to the surface modifying apparatus 33 by the modifying transfer device 32 a, and the bonding surface W2 j is reformed (step S111). Then, the lower wafer W2 is transferred from the surface modifying apparatus 33 to the load lock chamber 31 by the modifying transfer device 32 a. The load lock chamber 31 is switched from the depressurized atmosphere to the atmospheric pressure atmosphere, and the delivery of the lower wafer W2 is performed (step S112).

Next, the lower wafer W2 is transferred from the load lock chamber 31 to the surface hydrophilizing apparatus 34 by the transfer device 61. The bonding surface W2 j is made hydrophilic and is cleaned (step S113).

Next, the hydrophilized lower wafer W2 is transferred to the position adjusting device 51 by the transfer device 61, and the horizontal orientation of the lower wafer W2 is adjusted (step S114). At this time, the lower wafer W2 is in a state in which the bonding surface W2 j serves as an upper surface.

Next, the lower wafer W2 having the bonding surface W2 j as an upper surface is transferred to the substrate temperature control device 42. The lower wafer W2 is sucked and held by the second temperature control holding plate 42 b, and the temperature of the lower wafer W2 is controlled (step S115). In the substrate temperature control device 42, for example, the lower wafer W2 is controlled to have a higher temperature than the upper wafer W1.

In the above-described steps S101 to S106 and S109 to S115, the transfer of the upper wafer W1 and the lower wafer W2 by the transfer device 61 is performed by the second holding part 62 b. In the steps S107 and S108, the transfer of the upper wafer W1, inverted so that the bonding surface W1 j serves as a lower surface, is performed by the first holding part 62 a. However, the present disclosure is not limited to thereto.

Subsequently, the transfer device 61 receives the upper wafer W1 and the lower wafer W2 from the substrate temperature control device 42 at the same time, i.e., simultaneously (step S116). Then, the position detecting parts 70 a to 70 d detect the positions of the upper wafer W and the lower wafer W2 held by the transfer device 61 (step S117). Next, the transfer device 61 transfers the upper wafer W1 and the lower wafer W2 to the bonding apparatus 41 (step S118).

Next, the first holding part 62 a moves the upper wafer W1 to an appropriate position below the upper chuck 230 based on the position of the upper wafer W1 detected earlier. Then, the upper wafer W1 is sucked and held by the upper chuck 230 (step S119).

Next, the second holding part 62 b moves the lower wafer W2 to an appropriate position above the lower chuck 231 based on the detected position of the lower wafer W2 and causes the lower wafer W2 to be sucked and held by the lower chuck 231 (step S120).

Subsequently, in the bonding apparatus 41, the horizontal position adjustment of the upper wafer W1 held by the upper chuck 230 and the lower wafer W2 held by the lower chuck 231 is performed (step S121). Next, the vertical position adjustment of the upper wafer W1 held by the upper chuck 230 and the lower wafer W2 held by the lower chuck 231 is performed (step S122).

Next, the central portion W1 a of the upper wafer W1 and the central portion W2 a of the lower wafer W2 are brought into contact with each other and pressed against each other by the pushing member 250 (step S123). Then, the upper wafer W1 and the lower wafer W2 are bonded by an intermolecular force (step S124).

The laminated wafer T in which the upper wafer W1 and the lower wafer W2 are bonded is transferred to the transition 54 by the second holding part 62 b of the transfer device 61 (step S125). Thereafter, the laminated wafer T is transferred to the cassette C3 on a predetermined mounting plate 11 by the transfer device 22 of the loading/unloading station 2. Thus, a series of processes is completed.

As described above, the bonding system 1 according to the embodiment includes the transfer device 61 configured to transfer the upper wafer W1 and the lower wafer W2 to the bonding apparatus 41 that bonds the upper wafer W1 and the lower wafer W2. Furthermore, the bonding system 1 includes the first temperature control holding plate 42 a configured to hold the upper wafer W1 from the upper surface side, and the second temperature control holding plate 42 b provided under the first temperature control holding plate 42 a and configured to hold the lower wafer W2 from the lower surface side so that the lower wafer W2 faces the upper wafer W1.

The transfer device 61 includes the first holding part 62 a capable of holding the upper wafer W1 from the upper surface side, and the second holding part 62 b provided below the first holding part 62 a and capable of holding the lower wafer W2 from the lower surface side so that the lower wafer W2 faces the upper wafer W1. The first and second holding parts 62 a and 62 b receive the upper wafer W1 and the lower wafer W2 held by the first and second temperature control holding plates 42 a and 42 b, at the same time, from the first and second temperature control holding plates 42 a and 42 b, and hold the upper wafer W1 and the lower wafer W2. Thus, it is possible to shorten the processing time for transferring the upper wafer W1 and the lower wafer W2 to the bonding apparatus 41.

In the above-described embodiment, one load lock chamber 31 is provided. However, the present disclosure is not limited thereto. Two or more load lock chambers may be provided. In addition, the number of the transitions 31 a 1 and 31 a 2 in the load lock chamber 31 may be one or three or more.

In the bonding system 1 described above, the substrate temperature control device 42 is disposed adjacent to the bonding apparatus 41. However, the present disclosure is not limited thereto. For example, the substrate temperature control device 42 may be disposed at another location such as the third processing block G3 or the like. Furthermore, in the bonding system 1, the substrate temperature control device 42 may be removed.

In the above description, the upper wafer W1 or the like is held by vacuum suction or mounting. However, the present disclosure is not limited thereto. For example, a mechanical chuck for mechanically holding a substrate or an electrostatic chuck for holding a substrate with an electrostatic attraction force may be appropriately used.

According to the present disclosure in some embodiments, it is possible to shorten a processing time for transferring first and second substrates to a bonding apparatus.

Additional effects and modifications can be easily derived by those skilled in the art. Thus, the broader aspects of the present disclosure are not limited to the specific details and representative embodiments shown and described as above. Accordingly, various modifications are available without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents. 

What is claimed is:
 1. A bonding system comprising: a substrate transfer device configured to transfer a first substrate and a second substrate to a bonding apparatus for bonding the first substrate to the second substrate; a first holding plate configured to hold the first substrate from an upper surface side; and a second holding plate disposed below the first holding plate and configured to hold the second substrate from a lower surface side so that the second substrate faces the first substrate, wherein the substrate transfer device includes a first holding part capable of holding the first substrate from the upper surface side, and a second holding part disposed below the first holding part and capable of holding the second substrate from the lower surface side so that the second substrate faces the first substrate, and the first holding part and the second holding part are configured to receive the first substrate held by the first holding plate and the second substrate held by the second holding plate at the same time from the first holding plate and the second holding plate, and to hold the first substrate and the second substrate.
 2. The bonding system of claim 1, further comprising a position detecting part disposed in a direction perpendicular to a surface of the first substrate held by the first holding part and a surface of the second substrate held by the second holding part, and configured to detect a position of the first substrate and a position of the second substrate, wherein the second holding part is configured to hold the second substrate in a state in which a center of the second substrate is shifted from a center of the first substrate, and the position detecting part is configured to detect a peripheral edge of the first substrate, to detect a portion of a peripheral edge of the second substrate exposed from the first substrate in a plan view due to the center of the second substrate being shifted from the center of the first substrate, and to detect the position of the first substrate and the position of the second substrate based on the detected peripheral edge of the first substrate and the detected portion of the peripheral edge of the second substrate.
 3. The bonding system of claim 2, wherein the second holding plate is configured to hold the second substrate before being held by the second holding part, in a state in which the center of the second substrate is shifted from the center of the first substrate held by the first holding plate.
 4. The bonding system of claim 3, wherein at least one of the first holding plate and the second holding plate includes a temperature control mechanism configured to control a temperature of the first substrate or a temperature of the second substrate.
 5. The bonding system of claim 3, wherein the second holding plate is configured to hold the second substrate by vacuum suction. 